It is well known that an SCP camshaft can be very sensitive to component manufacturing tolerances and that the component parts must be made to an accurate specification in order for the camshaft to function correctly. This has an adverse effect upon the manufacturing costs of the camshaft.
In particular, the alignment of the holes in the drive shaft and the cam lobes through which each connecting pin is fitted is critical. If significant misalignment is present, the fitting of the connecting pin will act to align the holes and this will cause the drive shaft to lock in its bearings inside the camshaft tube. Variation in components due to manufacturing tolerances can therefore result in the inner shaft being unable to rotate relative to the outer tube of the camshaft. An example of the current practice for connecting cam lobes to the inner drive shaft is shown in GB-A-2375583.